I to also have a 2000 civic SI but in black lol. If you want a good sounding muffler thats loud i would say maybe HKS or Greddy. Me I don't really like my car to loud because i dont want to me to noticed by people and i dont want to want it to be the reason why i get pulled over so i went with a Tanabe hyper madeline for the low deep sound. If you want a good turbo for the SI i was told Turbonetics but you have to always keep doing oil changes and always working on the turbo. I think the best for the SI is maybe HKS since i dont know to mucha bout turbo for SI's and the dc headers you asked for is pretty much what i have and it works great. Instead of short ram intake i would rather go with cold air since thats what i have but the bad thing is you have to be carful with water since its more lower.